I’m trying to understand what my car is likely to weigh and what people can get them down to.

Does anybody have any real data?
1. Weight of your standard car, with options and ideally even fuel level
2. Weight of a modified car, with options and ideally even fuel level

I’m keen on real measured data, not quotes from the handbook / web.

I’m not thinking about reducing weight, just curious for now.

I don't understand why handbook quotes wouldn't be relevant? That should be a valid enough starting point assuming a stock car.

2003 Mercedes-Benz CLK55 AMG

Luxury car

Description

4.5/5 · Kelley Blue Book
Model: 2003 Mercedes-Benz CLK-Class
Horsepower: 362 hp
Engine: 5.4 L V8
Curb weight: 3,635 lbs
MPG: 17 city / 24 highway
Transmission: 5-speed automatic
Tire size: Front: P225/45R17, rear: P245/40R17
Torque: 376 lb-ft

Are you going to invest in carbon or plastic body panels (hood, trunk, fenders); remove the A/C, back seats? May as well do a manual transmission swap while you're at it. :o

If I get my fat *** on a better exercise regime, I'll save more weight in the car than most reduction programs like forged wheels.